2007
A2A hydroelectric power plant in Grosio
Grosio, Sondrio
The surgery was performed at the A2A hydroelectric power plant in Grosio, where the replacement of the high voltage cable support poles.
The new poles were to be positioned at about 3 metres distance from the existing ones, which, however, could not be removed before the new supports were installed, as they were still active in maintaining the line.
The main complexity of the intervention stemmed from the fact that the foundations of the new piles fell exactly at the top of a service pedestrian tunnel below, connected to the power plant. To ensure the stability of the ground and structural safety during excavation and replacement, it was necessary to build a containment Berliner close to the existing poles.
The Berliner, consisting of a series of vertically arranged micropiles connected by two metal crowning beams, It had the function of supporting the ground and preventing subsidence or deformation in the area of interference with the tunnel. This temporary support system ensured the full stability of the site during the excavation operations and the installation of the new structural elements.
Completata la berlinese, si è proceduto con lo scavo fino al raggiungimento della sommità del cunicolo, sul quale sono stati realizzati two Ø 1000 mm cores. All’interno di questi fori sono stati inseriti i pali prefabbricati, successivamente stabilizzati mediante getto di calcestruzzo, eseguito direttamente dal cunicolo, a costituire la fondazione dei nuovi pali.
Once the installation and consolidation of the new posts is complete, the power lines sono state trasferite sull’impianto aggiornato, consentendo di rimuovere in piena sicurezza i pali e le fondazioni esistenti, completando l’intervento senza interferire né con la funzionalità della centrale, né con la stabilità delle opere preesistenti.
